The Remington model # 7188 that was issued in semi/full auto during the V/N war was a very good weapon. The main differance between it and a std. 1100 was just the trigger group and ext tube for an extra 3 rds of ammo for 8rds total.
The selector for semi vs full was located where the normal 1100 safety has always been. In full auto you could hear the rate of fire change.
The weapon was most always issued to Seal Teams, however a few made their way into other branchs and units. It was a great point man, ambush, hooch clearing weapon. The only draw back was the limited (8) round count.